Attempt to invoke virtual method ...t.RecyclerView.setAdapter(..RecyclerView$Adapter)' on a null object reference

public class NotificationFragment extends Fragment {

    RecyclerView notificationRv;
    private FirebaseAuth firebaseAuth;
    private ArrayList<ModelNotification> notificationsList;
    private NotificationAdapter notificationAdapter;




    public NotificationFragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_blank, container, false);

        notificationRv = view.findViewById(R.id.notificationRv);
        firebaseAuth = FirebaseAuth.getInstance();
        getAllNotifications();

        return view;
    }

    private void getAllNotifications() {
        notificationsList = new ArrayList<>();
        DatabaseReference ref = FirebaseDatabase.getInstance("https://helper-70936-default-rtdb.firebaseio.com/").getReference("users");
        ref.child(firebaseAuth.getUid()).child("Notifications")
                .addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                        notificationsList.clear();
                        for(DataSnapshot ds: dataSnapshot.getChildren()){
                            ModelNotification model = ds. getValue(ModelNotification.class);

                            notificationsList.add(model);
                        }
                        notificationAdapter = new NotificationAdapter(getActivity(), notificationsList);
                        notificationRv.setAdapter(notificationAdapter);

                    }

                    @Override
                    public void onCancelled(@NonNull DatabaseError databaseError) {

                    }
                });

    }
}